--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/viewers/TreeStructureAdvisor.d	Tue Apr 14 11:35:29 2009 +0200
@@ -0,0 +1,62 @@
+/*******************************************************************************
+ * Copyright (c) 2008 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ ******************************************************************************/
+module org.eclipse.jface.databinding.viewers.TreeStructureAdvisor;
+
+import java.lang.all;
+
+/**
+ * Instances of this class can be used to improve accuracy and performance of an
+ * {@link ObservableListTreeContentProvider} or an
+ * {@link ObservableSetTreeContentProvider}. This class is intended to be
+ * subclassed by clients.
+ * 
+ * @since 1.2
+ * 
+ */
+public abstract class TreeStructureAdvisor {
+
+    /**
+     * Returns the parent for the given element, or <code>null</code>
+     * indicating that the parent can't be computed. In this case the
+     * tree-structured viewer can't expand a given node correctly if requested.
+     * The default implementation returns null; clients should override.
+     * 
+     * @param element
+     *            the element
+     * @return the parent element, or <code>null</code> if it has none or if
+     *         the parent cannot be computed
+     */
+    public Object getParent(Object element) {
+        return null;
+    }
+
+    /**
+     * Returns whether the given element has children, or <code>null</code> if
+     * the actual children collection should be consulted. The default
+     * implementation returns null; clients should override.
+     * <p>
+     * Intended as an optimization for when the viewer does not need the actual
+     * children. Clients may be able to implement this more efficiently than
+     * <code>getChildren</code>.
+     * </p>
+     * 
+     * @param element
+     *            the element
+     * @return <code>Boolean.TRUE</code> if the given element has children,
+     *         <code>Boolean.FALSE</code> if it has no children, or
+     *         <code>null</code> if the children collection should be
+     *         consulted.
+     */
+    public Boolean hasChildren(Object element) {
+        return null;
+    }
+
+}